why quartz sand is preferred in cement mortar industries to bag it instead of river sand.?

Question

electrical resistivity may be a cause,but why river sand cant take the place of ready mix dry mortar of cement sand mix when packed in bags for long time for plastering, brick -block laying of walls.cracks in walls develops due to good river sand or due to cement if standard ratio maintained.why quartz sand cement mortar manufacturer guaranteed for non cracking of walls.why cement manufactures are using quartz silica sand for their quality cement.

Answer 1

In cement mortar,very fine clay particles are to be completely avoided as defined by curves of gradation of sand v/s sieve size.These very fine particles are responsible for cracking of walls by making mortar more porous.

In a glass of water,if we pour sand,then very fine clay particles settle above normal sand particles and can be visually seen.Or by rubbing dry sand in hand and dropping it,if some very fine particles stick to palm,then it indicates presence of clay particles.

In river sand,clay particles are present,so it has to be avoided in cement mortar industries.

Answer 2

I didn't get it clearly what do u want...Normally for concrete ,river sand is using. It should be satisfied IS standards. Zone IV is not using since this sand is fine one., not suitable for concreting. Quartz sand is using for Cement testing for knowing properties of Cement mortar.Most of the works llike masonry work,plastering and mass concrete by river sand . nowadays crusher sand also is used for concreting (it should have been passed the sieve 4.75 mm)

Answer 3

tricky aspect. do a search from yahoo and bing. this can assist!